Heretofore, projectors have been used for presentations at conferences, a home theater, or the like. As light sources that are used in these projectors, an ultrahigh pressure mercury lamp with a pair of electrodes has been used. Since abrasions occur on the electrodes or the lamp is clouded due to deterioration with age as the projector is continuously used, the lamp has a short life span of approximately 2000 hours.
In order to resolve this problem, a method has been disclosed in JP-A-2001-155882 in which a microwave is generated using a magnetron, and a non-electrode light source lamp (corresponding to a non-electrode light emitting tube in this invention) is turned on by the microwave.
Specifically, a microwave radiating optical source device is applied to an image display device. At this time, the microwave radiating optical source device includes a magnetron that generates a microwave, a resonator having a hole that resonates the microwave and exits light, a non-electrode light source lamp that seals a radiating medium that is provided in the resonator and is radiated by the microwave, and a pair of magnetic force generating units that generate magnetic lines of force substantially in a right angle direction with respect to the exit direction of the exit light from the non-electrode light source lamp, and generate magnetic lines of force in directions opposite to each other with the non-electrode light source lamp interposed therebetween. As such, the non-electrode optical source lamp makes the microwave radiating optical source device tolerable for continuous use, therefore, the life span of the microwave radiating optical source device can be increased.
However, a microwave radiating optical source device that is disclosed in JP-A-2001-155882 uses a magnetron, and in this microwave radiating optical source device, the size and weight thereof may be increased. Further, a magnetron oscillating tube that forms the microwave radiating optical source device has one type of a vacuum tube structure where a filament (cathode) and an anode are provided therein. As such, the non-electrode optical source lamp has a long life span, but the magnetron oscillating tube does not have a long life span due to the damage in the filament or the abrasion in the electrode. In addition, when the magnetron oscillating tube is driven, a high voltage of several kV needs to be applied to the anode, which increases the size of a power supply circuit.
The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide an optical source device and a projector including the optical source device in which a microwave is used to reduce a size thereof, and to increase a life span thereof.